(i) Field of the Invention
The present invention relates to a motor compressor comprising a motor element and a compression element which is driven by a rotating shaft connected to the motor element in a closed vessel.
(ii) Description of the Related Art
Heretofore, this kind of motor compressor has been disclosed in Japanese Patent Application Laid-Open Nos. 288180/1998 (FO4C29/00) and 350444/1993 previously filed by the present applicant. An induction motor, a DC motor, and so forth are used as the motor of the conventional motor compressor, but the DC motor is designed so that a laminated thickness of a permanent magnet and a rotor is the same as that of a stator in case that it is a rare earth permanent magnet motor, and the laminated thickness of the rotator and the permanent magnet is higher than that of the stator in case that it is a ferrite permanent motor.
Next, this conventional type of the motor 100 will be explained by use of FIG. 21 and FIG. 22. A closed vessel 101 in the drawings contains a motor 102 (e.g., a DC motor) as the motor element in the internal upper side thereof, and a compression element 103 being rotatably driven by this motor 102 in the lower side. The closed vessel 101, which comprises a cylindrical shell 101A with the upper end thereof opened, and an end cap 101B that clogs the upper end opening of the shell 101A, is a two-section configuration and is configured by capping the cylindrical shell 101A with the end cap 101B to close it with a high frequency deposition, and so forth, after inserting the motor 102 and the compression element 103 within the shell 101A. Furthermore, the bottom within the shell 101A of the closed vessel 101 becomes an oil sump SO.
The motor 102 is constituted of a stator 104 fixed to the internal wall of the closed vessel 101 and a rotator 105 with a rotating shaft 106 centered rotatably supported in the inside of this stator 104. The stator 104 is constituted of a stator core 174 configured by laminating a plurality of steel sheets for stator sheets with substantially a donut shape, and a stator winding (drive coil) 107 for applying rotating magnet field to the rotator 105, which is mounted with a distributed winding technique on a plurality of teeth formed in an internal periphery of this stator core 174. Moreover, the peripheral surface of this status core 174 contacts and is fixed to the internal wall of the shell 101A of the closed vessel 101.
In this case, a plurality of notches 176 are formed in the peripheral surface of the stator core 174, and these notches 176 are spaced from the internal wall of the shell 101A, wherein a path 177 is configured.
The compression element 103 comprises a first cylinder for a rotary 109 and a second cylinders for a rotary 110 separated by an intermediate parting stop 108. To each of the cylinder 109 and 110 are attached eccentrics 111 and 112 being rotatably driven by the rotating shaft 106, and each eccentricity of the eccentrics 111 and 112 is 180xc2x0 degree out of phase from the other.
113 and 114 indicate a first roller and a second roller that rotate within the cylinder 109 and 110, respectively, and each rotates within the cylinders by the rotation of the eccentrics 111 and 112, respectively. 115 and 116 indicate a first frame and a second frame. The first frame 115 causes compressed air to be formed between the parting stop 108 and the frame with the cylinder 109 closed, and the second frame 116 also causes compressed air to be formed between the parting stop 108 and the frame with the cylinder 110 closed. Furthermore, the first frame 115 and the second frame 116 comprise bearings 117 and 118, respectively, that rotatably and axially support the lower portion of the rotating shaft 106.
119 and 120 indicate cap mufflers which are attached so as to cover the first frame 115 and the second frame 116. In addition, the cylinder 109 and the cap muffler 119 are in mutual communication by a communicating hole (not shown) provided in the first frame 115, and the cylinder 110 and the cap muffler 120 are also in mutual communication by a communicating hole (not shown) provided in the second frame 116, 121, which is a bypass pipe provided outside the closed vessel 101, is in communication with the internal side of the cap muffler 120.
122 is a vent pipe provided on the top of the closed vessel 101, and 123 and 124 are suction pipes that connect to the cylinder 109 and 110 respectively. Furthermore, 125, which is a closed terminal, is for supplying a power from the external side of the closed vessel 101 to the stator winding 107 (a lead wire that connects the closed terminal 125 and the stator winding 107 is not shown in the figure).
A rotator core 126 of the rotator 105 has a plurality of steel sheets for a rotator with a predetermined shape stamped from magnetic steel sheets with thickness 0.003 mm to 0.007 mm to be laminated to caulk each other for integration.
In this case, the steel sheets for a rotor of the rotator core 126 are stamped from magnetic steel sheets so that salient poles 128, 129, 130 and 131 are formed that construct a quadrupole, and 132, 133, 134 and 135 are concavities provided so that the salient poles are formed between each of the salient poles 128, 129, 130 and 131, and the other respectively.
Slots 141, 142, 143 and 144 for inserting a magnetic substance 145 (permanent magnet) correspond to each of the salient poles 128, 129, 130 and 131, respectively, and they are concentrically slotted on the periphery side of the rotator core 126 along the direction of an axis of the rotating shaft 106.
Furthermore, a hole 146, into which the rotating shaft 106 is shrink-fitted, is formed at the center of the rotator core 126. Each rotator core 126 is formed by caulking each other for integration after laminating a plurality of steel sheets for a rotator.
The magnetic substance 145 set forth above is constituted of a rare earth magnetic material such as a praseodymium magnet material or a neodymium magnetic material whose surface is plated with nickel or the like, and the external shape thereof is to be a profile rectangle, and, as a whole, to be rectangular. Each of the slots 141, 142, 143 and 144 is to be sized so that this magnetic substance 145 is inserted. Moreover, 166 and 167, which are flat-shape end members being attached to the upper and the lower end of the rotator core 126, are formed of non-magnetic materials such as stainless steel, brass or the like in a nearly discus shape.
In addition, 172, which is located above the end member 166, is a discus-shape plate for separating oil attached to the rotator 105, and 173 is a balancing weight attached between the plate 172 and the end surface 166.
In such a configuration, when a power is applied to the stator winding 107 of the stator 104 of the motor 102, a rotating magnetic filed is formed to rotate the rotator 105. Rollers 113, and 114 within the cylinder 109 and 110 are eccentrically rotated via the rotating shaft 106 by this rotation of the rotator 105, and suction gas sucked from the suction 123 and 124 is compressed.
The compressed high-pressure gas is vented within the cap muffler 119 and from the cylinder 109 via the communicating hole, and is vented within the closed vessel 101 from the vent hole (not shown) formed in this cup muffler 119. On the other hand, from the cylinder 110, the compressed high-pressure gas is vented into the cup muffler 120 via the communicating hole, and is vented into the closed vessel 101 through the bypass pipe 121.
The vented high-pressure gas passes through a gap within the motor 102 to reach the vent pipe 122, and is vented to the external side. On the other hand, oil is contained in the gas, but this oil, which is separated by the plate 172, and the like, until it reaches the vent pipe 122, is directed externally by a centrifugal force, and flows down to the oil gathering SO through the path 177.
Such a motor 102 provided in the motor compressor 100 has been designed so that, in case that the magnetic substance 145 is a rare earth permanent magnet, a thickness dimension of a permanent magnet and the rotator 105, and a laminated thickness of the stator 104 are almost the same, and in case that the magnetic substance 145 is a ferrite permanent magnet, the laminated thickness of the permanent magnet and the rotator 105 is higher than that of the stator 104.
However, in the DC motor (electric motor) for use in the compressor, a radial magnetic attraction/repulsion force of the stator is big, as compared with a normal reduction motor. For this reason, a yoke of the motor is shaken, which has been a factor to the increase in noise of the motor compressor. In particular, in the motor using a rare earth permanent magnet with a high magnetic force and in a magnetic-pole concentrated winding motor having less number of slots, variation in magnetic flux is bigger than that of a motor having many slots and, accordingly, the problem existed that the noise reduction is a big task.
In addition, the vibration shaken at the teeth of the stator core shook the yoke of the stator to directly vibrate the shell at the contact area to the shell. The problem existed that this is also a factor to the increase in noise of the motor compressor.
The present invention has been accomplished to solve such conventional tasks, and an objective of the present invention is to provide a motor compressor that can drastically reduce noise by lessening a contact area between a stator and a shell.
Namely, a first aspect of the present invention is directed to a motor compressor comprising a motor element and a compression element which is driven by a rotating shaft connected to the motor element in a closed vessel, wherein the motor element is constituted of a stator having a stator core that contacts and is fixed to the inside wall of the closed vessel, and a rotator having a magnetic substance which is attached to a rotating shaft and rotatably supported in the inside of the stator; and H less than Ho is satisfied wherein H is a dimension in a rotating shaft direction of an area in which the stator core contacts the closed vessel, and Ho is a dimension in the rotating shaft direction of the above stator core.
Furthermore, a second aspect of the present invention is directed to a motor compressor comprising a motor element and a compression element which is driven by a rotating shaft connected to the motor element in a closed vessel, wherein the motor element is constituted of a stator having a stator core that contacts and is fixed to the inside wall of the closed vessel, and a rotator having a magnetic substance which is attached to a rotating shaft and rotatably supported in the inside of the stator; and Hmg less than Ho is satisfied wherein Hmg is a dimension of the magnetic substance in the direction of the rotating shaft and Ho is a dimension of the above stator core in the direction of the rotating shaft.
In addition, a third aspect of the present invention is directed to a motor compressor comprising a motor element and a compression element which is driven by a rotating shaft connected to the motor element in a closed vessel, wherein the motor element is constituted of a stator having a stator core that contacts and is fixed to the inside wall of the closed vessel, and a rotator having a magnetic substance which is attached to the rotating shaft and rotatably supported in the inside of the stator; and H less than Ho and Hmg less than Ho are satisfied wherein H is a dimension in a rotating shaft direction of an area in which the stator core contacts the closed vessel, Ho is a dimension in the rotating shaft direction of the above stator core, and Hmg is a dimension of the magnetic substance in the direction of the rotating shaft.
Furthermore, in addition to the first to third inventions, the motor compressor of the present invention is configured to set a ratio of a dimension H to a dimension Ho at 0.2xe2x89xa6H/Hoxe2x89xa60.8.
In addition, in addition to the second and third inventions, the motor compressor of the present invention is configures to set a ratio of dimension Hmg to a dimension Ho at 0.2xe2x89xa6H/Hoxe2x89xa60.98.
Furthermore, in addition to the above-mentioned inventions, in the motor compressor of the present invention, the magnetic substance is constituted of the rare earth magnetic material; and a ratio of L to D, L/D less than 1.1 is satisfied wherein L is a dimension of the above rotator core in the direction of the rotating shaft and D is a diameter of the rotator core of the rotator; and a ratio of t to the dimension Hmg, t/Hmg less than 0.1 is satisfied wherein t is a thickness dimension of the magnetic substance.
Additionally, the present invention is directed to a cooling apparatus in which a refrigerant circuit is constituted of the motor compressor of the above-mentioned invention, a condenser, a pressure reducing apparatus and an evaporator.